The main function of the skin is to protect body from negative environmental influences. physical barrier permeability mainly represented by stratum corneum; however, other layers epidermis and dermis are its important components. mechanical strength provided intercellular contacts in structural proteins dermis. chemical-biological includes lipids, acids, natural moisturizing factor antimicrobi...

1. We have recently shown that the stellate cells, under normal conditions, contain a majority (more than 80%) of the total store of retinol in liver (Blomhoff et al. 1985). 2. In the present work we have studied the role of the various liver cells in rats of different ages, sex and vitamin A status. 3. In most of these groups of rats, storage of retinol in parenchymal cells was proportional to...

We recently demonstrated a rapid up-regulation of serum retinol-retinol binding protein-transthyretin concentration in rats with short-term acute renal failure. We examine the effect of retinoic acid and apo-retinol binding protein (apo-RBP) on the up-regulation of serum retinol in renal failure. Injection of retinoic acid (10 micrograms) into rats with acute renal failure or sham-operated rats...

Normal, healthy, free-living adults ingested either 18 g/d olestra, with or without 1.1 mg tocopheryl acetate/ g olestra, or 18 g/d triglyceride placebo, for 16 wk in a double-blind, placebo-controlled study. Serum concentrations of a-tocopherol, a-carotene, b-carotene, lycopene, lutein/zeaxanthin, retinol and cholesterol were measured biweekly. Serum 25-hydroxyvitamin D concentration, prothrom...

12-O-retinoylphorbol-13-acetate (RPA), an incomplete tumor promoter of the phorbol ester type and protein kinase C (PKC) activator, consists of two characteristic structural elements: the phorbol body and the retinoyl ester chain. Therefore, possible binding of the incomplete tumor promoter RPA to the human transport protein retinol-binding-protein (RBP) has been examined by molecular modeling ...

The safe upper limit for inclusion of vitamin A in complete diets for growing dogs is uncertain, with the result that current recommendations range from 5.24 to 104.80 μmol retinol (5000 to 100 000 IU vitamin A)/4184 kJ (1000 kcal) metabolisable energy (ME). The aim of the present study was to determine the effect of feeding four concentrations of vitamin A to puppies from weaning until 1 year ...

Understanding of the stereospecificity of enzymatic reactions that regenerate the universal chromophore required to sustain vision in vertebrates, 11-cis-retinal, is needed for an accurate molecular model of retinoid transformations. In rod outer segments (ROS), the redox reaction involves all-trans-retinal and pro-S-NADPH that results in the production of pro-R-all-trans-retinol. A recently id...

Retinol and its derivative, retinoic acid, have pleiotropic functions including vision, immunity, hematopoiesis, reproduction, cell differentiation/growth, and development. Non-alcoholic fatty liver disease (NAFLD) is one of the most common diseases in developed countries and encompasses a broad spectrum of forms, ranging from steatosis to steatohepatitis, which develops further to cirrhosis. R...

The regeneration of 11-cis-retinal, the universal chromophore of the vertebrate retina, is a complex process involving photoreceptors and adjacent retinal pigment epithelial cells (RPE). 11-cis-Retinal is coupled to opsins in both rod and cone photoreceptor cells and is photoisomerized to all-trans-retinal by light. Here, we show that RPE microsomes can catalyze the reverse isomerization of 11-...

Vitamin A (retinol) is a nutrient that is essential for developmental regulation but toxic in large amounts. Previous genetic studies have revealed that alcohol dehydrogenase Adh1 is required for efficient clearance of excess retinol to prevent toxicity, thus demonstrating that the mechanism involves oxidation of excess retinol to retinoic acid (RA). Whereas Adh1 plays a dominant role in the fi...